Tonne-kilometre
   HOME

TheInfoList



OR:

The units of measurement in transportation describes the
unit of measurement A unit of measurement is a definite magnitude (mathematics), magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can ...
used to express various
transportation Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline, ...
quantities Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit ...
, as used in statistics, planning, and their related applications.


Transportation quantity

The currently popular units are:


Length of journey

*
kilometre The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...
(km) or kilometer is a
metric Metric or metrical may refer to: * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathem ...
unit used, outside the US, to measure the length of a journey; * the international
statute mile The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 Engli ...
(mi) is used in the US; 1 mi = 1.609344 km *
nautical mile A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute ( of a degree) of latitude. Today ...
is rarely used to derive units of transportation quantity.


Traffic flow

* vehicle-kilometre (vkm) as a measure of
traffic flow In mathematics and transportation engineering, traffic flow is the study of interactions between travellers (including pedestrians, cyclists, drivers, and their vehicles) and infrastructure (including highways, signage, and traffic control devi ...
, determined by multiplying the number of vehicles on a given road or traffic network by the average length of their trips measured in kilometres. * vehicle-mile (, or VMT) same as before but measures the trip expressed in miles.


Passenger


Payload quantity

*
Passenger A passenger (also abbreviated as pax) is a person who travels in a vehicle, but does not bear any responsibility for the tasks required for that vehicle to arrive at its destination or otherwise operate the vehicle, and is not a steward. The ...
; Person (often abbreviated as either "pax" or "p.")


Passenger-distance

Passenger-distance is the distance (km or miles) travelled by passengers on
transit vehicle Public transport (also known as public transportation, public transit, mass transit, or simply transit) is a system of transport for passengers by group travel systems available for use by the general public unlike private transport, typical ...
s; determined by multiplying the number of unlinked passenger trips by the average length of their trips. * passenger-kilometre or pkm internationally; * passenger-mile (or pmi ?) sometimes in the US; 1 pmi = 1.609344 pkm


Passengers per hour per direction

Passengers per hour per direction Passengers per hour per direction (p/h/d), passengers per hour in peak direction (pphpd) or corridor capacity is a measure of the route capacity of a rapid transit or public transport system. Definition The corridor capacity in the passenger t ...
(pphpd) measures the maximum
route capacity Route capacity is the maximum number of vehicles, people, or amount of freight than can travel a given route in a given amount of time, usually an hour. It may be limited by the worst bottleneck (engineering), bottleneck in the system, such as a ...
of a transport system.


Passengers per bus hour

A system may carry a high number of passengers per distance (km or mile) but a relatively low number of passengers per bus hour if vehicles operate in congested areas and thus travel at slower speed.


Passengers per bus distance

A transit system serving a community with a widely dispersed population must operate circuitous routes that tend to carry fewer passengers per distance (km or mile). A higher number is more favorable.


Freight

Freight is measured in mass-distance. A simple unit of freight is the kilogram-kilometre (kgkm), the service of moving one kilogram of payload a distance of one kilometre.


Payload quantity

*
kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially ...
(kg), the standard SI unit of mass. *
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
(t), a non- SI but an accepted metric unit, defined as 1,000
kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially ...
s. * "
short ton The short ton (symbol tn) is a measurement unit equal to . It is commonly used in the United States, where it is known simply as a ton, although the term is ambiguous, the single word being variously used for short, long, and metric ton. The vari ...
" is used in the US; 1 short ton = 2,000 pounds = 0.907 tonnes. :1 t = (1/0.907) short tons = 1.102 short tons.


Payload-distance

* kilogram-kilometre (kg⋅km), moving 1 kg of cargo a distance of 1 km; * tonne-kilometre or kilometre-tonne (t⋅km or km⋅t, also tkm or kmt), the transportation of one
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
over one
kilometre The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...
; 1 tkm = 1,000 kgkm. * ton-mile in the US: 1 ton-mile * ( 0.907185 t / short ton) * ( 1.609344 km / mile ) = 1.460 tkm


Usage

The
metric Metric or metrical may refer to: * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathem ...
units (pkm and tkm) are used internationally. (In
aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air ...
where
United States customary units United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English units ...
are widely used, the
International Air Transport Association The International Air Transport Association (IATA ) is a trade association of the world's airlines founded in 1945. IATA has been described as a cartel since, in addition to setting technical standards for airlines, IATA also organized tariff ...
(IATA) releases its statistics in the metric units.) In the US, sometimes United States customary units are used.


Derivation

The
dimension In physics and mathematics, the dimension of a Space (mathematics), mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any Point (geometry), point within it. Thus, a Line (geometry), lin ...
of the measure is the product of the payload mass and the distance transported.


Example

A
semi truck A semi-trailer truck, also known as a semitruck, (or semi, eighteen-wheeler, big rig, tractor-trailer or, by synecdoche, a semitrailer) is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer a ...
traveling from Los Angeles to Chicago (approximate distance 2,015 miles) carrying 14 short tons of cargo delivers a service of 14 * 2,015 = 28,210 ton-miles of freight (equal to about 41,187 tkm).


Intermodal containers

Intermodal container An intermodal container, often called a shipping container, is a large standardized shipping container, designed and built for intermodal freight transport, meaning these containers can be used across different Mode of transport, modes of trans ...
traffic is commonly measured in
twenty-foot equivalent unit The twenty-foot equivalent unit (abbreviated TEU or teu) is an inexact unit of cargo capacity, often used for container ships and container ports.Rowlett, 2004. It is based on the volume of a intermodal container, a standard-sized metal box whic ...
s (TEUs), rather than cargo weight, e.g. a TEU-km would be the equivalent of one twenty-foot container transported one kilometer.


Transportation density

Transportation density can be defined as the payload per period, say passenger / day or tonne / day. This can be used as the measure of intensity of the transportation on a particular section or point of transportation infrastructure, say road or railway. This can be used in comparison with the construction, running costs of the infrastructure.


Fatalities by VMT

Fatalities by VMT (
vehicle miles traveled The units of measurement in transportation describes the unit of measurement used to express various transportation quantities, as used in statistics, planning, and their related applications. Transportation quantity The currently popular units ...
) is a unit for assessing road traffic fatalities. This metric is computed by dividing the fatalities by the estimated VMT. Usually, transport risk is computed by reference to the distance traveled by people, while for road traffic risk, only vehicle traveled distance is usually taken into account. In the United States, the unit is used as an aggregate in yearly federal publications, while its usage is more sporadic in other countries. For instance, it appears to compare different kind of roads in some publications as it had been computed on a five-year period between 1995 and 2000.http://dtrf.setra.fr/pdf/pj/Dtrf/0002/Dtrf-0002649/DT2649.pdf In the United States, it is computed per 100 million miles traveled, while internationally it is computed in 100 million or 1 billion kilometers traveled. According to the Minnesota Department of Public Safety, Office of Traffic Safety


Energy efficiency

Energy efficiency in transport The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depe ...
can be measured in L/100 km or miles per gallon (mpg). This can be normalized per vehicle, as in
fuel economy in automobiles The fuel economy of an automobile relates distance traveled by a vehicle and the amount of fuel consumed. Consumption can be expressed in terms of volume of fuel to travel a distance, or the distance traveled per unit volume of fuel consumed. S ...
, or per seat, as for example in
fuel economy in aircraft The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft. Efficiency is increased with better aerodynamics and by reducing weight, and with improved engine BSFC and propulsive efficiency or TSFC. Enduran ...
.


History

MacNeal 1994 discusses the history of this topic, exploring such units and how humans developed the current state of logically recognizing and naming them.


See also

* Available seat miles *
Passenger load factor Passenger load factor, or load factor, measures the capacity utilization of public transport services like airlines, passenger railways, and intercity bus services. It is generally used to assess how efficiently a transport provider fills seats ...
*
List of countries by rail usage This is a list of countries by rail usage. Usage of rail transport may be measured in tonne-kilometres (tkm) or passenger-kilometres (pkm) travelled for freight and passenger transport respectively. This is the number of tonnes or passengers ...


References


External links


Scheduled Passengers Carried, World Air Transport Statistics 51st Edition, IATA
provides an example of transportation statistics {{DEFAULTSORT:Transportation measurement Economic data Transport economics